Water-free antiperspirant compositions made up as a non-aerosol, stick, cream, gel, suspension or solution generally contain, in addition to the active sweat-reducing substances, at least one cosmetic oil as carrier for the particulate active sweat-reducing substance. So that the active antiperspirant substance suspended in the oil does not settle out during storage, commercial suspensions, gels, creams and sticks contain a suspending or thickening agent; in gels, e.g. hydrophobically modified hectorites as available, for example, with the trade name Bentone Gel from Rheox and Elementis Specialties, and in sticks, thickeners such as fatty alcohols and/or waxes.
In commercial water-free antiperspirant compositions, the active antiperspirant substance suspended in the water-free, oil-containing carrier is covered with an oil layer. However, this oil layer delays the release of the active antiperspirant substance in the effective water-soluble form.
In the prior art, water-containing antiperspirant creams with a water content of 43.9 wt. % are known from U.S. Pat. Nos. 5,118,497 and 5,017,360, which are emulsified with the aid of the commercial product Elfacos ST-37, an alkyl-modified polyether with the INCI name PEG-22/Dodecyl Glycol Copolymer, which has an HLB value of 2.4.
U.S. Pat. No. 6,613,338, and in particular WO 98/17238 A1, disclose sticks, in particular antiperspirant sticks, in the form of solid water-in-oil emulsions with a water content of 30-85 wt. %, which are emulsified with the aid of an alkyl-modified polyether of the general formula ACTIVATOR-(I) with the INCI name Methoxy PEG-22/Dodecyl Glycol Copolymer. This prior art gave the person skilled in the art no indication that alkyl-modified polyethers of the general formula ACTIVATOR-(I) can improve the release of the active antiperspirant substance from a water-free composition.
WO 2009/083547 A2 and WO 2009/083807 A2 teach that certain organosiloxane-oxyalkylene copolymers can improve the release of the active antiperspirant substance from a water-free composition. As a disadvantage of these substances, however, it has been shown that under certain circumstances, in particular when the cosmetic carrier contains little or no silicone oil, they are difficult to incorporate and to mix in homogeneously.
Desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with this background of the invention.